tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/* Inject a hwpoison memory failure on a arbitrary pfn */
2#include <linux/module.h>
3#include <linux/debugfs.h>
4#include <linux/kernel.h>
5#include <linux/mm.h>
6#include <linux/swap.h>
7#include <linux/pagemap.h>
8#include <linux/hugetlb.h>
9#include "internal.h"
10
11static struct dentry *hwpoison_dir;
12
13static int hwpoison_inject(void *data, u64 val)
14{
15 unsigned long pfn = val;
16 struct page *p;
17 struct page *hpage;
18 int err;
19
20 if (!capable(CAP_SYS_ADMIN))
21 return -EPERM;
22
23 if (!pfn_valid(pfn))
24 return -ENXIO;
25
26 p = pfn_to_page(pfn);
27 hpage = compound_head(p);
28 /*
29 * This implies unable to support free buddy pages.
30 */
31 if (!get_page_unless_zero(hpage))
32 return 0;
33
34 if (!hwpoison_filter_enable)
35 goto inject;
36
37 if (!PageLRU(p) && !PageHuge(p))
38 shake_page(p, 0);
39 /*
40 * This implies unable to support non-LRU pages.
41 */
42 if (!PageLRU(p) && !PageHuge(p))
43 return 0;
44
45 /*
46 * do a racy check with elevated page count, to make sure PG_hwpoison
47 * will only be set for the targeted owner (or on a free page).
48 * We temporarily take page lock for try_get_mem_cgroup_from_page().
49 * memory_failure() will redo the check reliably inside page lock.
50 */
51 lock_page(hpage);
52 err = hwpoison_filter(hpage);
53 unlock_page(hpage);
54 if (err)
55 return 0;
56
57inject:
58 printk(KERN_INFO "Injecting memory failure at pfn %lx\n", pfn);
59 return memory_failure(pfn, 18, MF_COUNT_INCREASED);
60}
61
62static int hwpoison_unpoison(void *data, u64 val)
63{
64 if (!capable(CAP_SYS_ADMIN))
65 return -EPERM;
66
67 return unpoison_memory(val);
68}
69
70DEFINE_SIMPLE_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
71DEFINE_SIMPLE_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n");
72
73static void pfn_inject_exit(void)
74{
75 if (hwpoison_dir)
76 debugfs_remove_recursive(hwpoison_dir);
77}
78
79static int pfn_inject_init(void)
80{
81 struct dentry *dentry;
82
83 hwpoison_dir = debugfs_create_dir("hwpoison", NULL);
84 if (hwpoison_dir == NULL)
85 return -ENOMEM;
86
87 /*
88 * Note that the below poison/unpoison interfaces do not involve
89 * hardware status change, hence do not require hardware support.
90 * They are mainly for testing hwpoison in software level.
91 */
92 dentry = debugfs_create_file("corrupt-pfn", 0200, hwpoison_dir,
93 NULL, &hwpoison_fops);
94 if (!dentry)
95 goto fail;
96
97 dentry = debugfs_create_file("unpoison-pfn", 0200, hwpoison_dir,
98 NULL, &unpoison_fops);
99 if (!dentry)
100 goto fail;
101
102 dentry = debugfs_create_u32("corrupt-filter-enable", 0600,
103 hwpoison_dir, &hwpoison_filter_enable);
104 if (!dentry)
105 goto fail;
106
107 dentry = debugfs_create_u32("corrupt-filter-dev-major", 0600,
108 hwpoison_dir, &hwpoison_filter_dev_major);
109 if (!dentry)
110 goto fail;
111
112 dentry = debugfs_create_u32("corrupt-filter-dev-minor", 0600,
113 hwpoison_dir, &hwpoison_filter_dev_minor);
114 if (!dentry)
115 goto fail;
116
117 dentry = debugfs_create_u64("corrupt-filter-flags-mask", 0600,
118 hwpoison_dir, &hwpoison_filter_flags_mask);
119 if (!dentry)
120 goto fail;
121
122 dentry = debugfs_create_u64("corrupt-filter-flags-value", 0600,
123 hwpoison_dir, &hwpoison_filter_flags_value);
124 if (!dentry)
125 goto fail;
126
127#ifdef CONFIG_MEMCG_SWAP
128 dentry = debugfs_create_u64("corrupt-filter-memcg", 0600,
129 hwpoison_dir, &hwpoison_filter_memcg);
130 if (!dentry)
131 goto fail;
132#endif
133
134 return 0;
135fail:
136 pfn_inject_exit();
137 return -ENOMEM;
138}
139
140module_init(pfn_inject_init);
141module_exit(pfn_inject_exit);
142MODULE_LICENSE("GPL");